The notices, handed out in November but announced on Monday, are the first made public by the regulator since it gained the authority in October. They also show that the FCA is pursuing alleged Libor offenders through civil action.

The FCA said it warned a manager at a bank who for more than three years condoned traders asking rate submitters to rig Libor figures and submitters making submissions based on those requests.

The manager enabled interest rate manipulation and allowed the same people to submit Libor numbers and trade derivatives linked to the benchmark.

The watchdog issued the second warning to a banker who made Libor submissions based on traders' requests and colluded with an interdealer broker to manipulate the rate.

The banker also colluded with traders at another bank by asking them to adjust their Libor submissions and responding to their requests to influence submissions.

The banker involved also made Libor submissions based on the interest derivative positions they managed themselves.

The FCA declined to say whether the bankers worked at the same bank or which banks were involved. The regulator's practice is not to name individuals unless it needs to do so to clear up speculation.

The statements show that other people were involved, meaning further public warnings are likely. Releasing details aims to reassure the public at an earlier stage that the FCA is taking action.

Libor is an interest rate used to set prices on £300tn worth of financial contracts around the world, from ordinary household mortgages to business loans. It was set by banks on a panel submitting figures for their borrowing costs to the British Bankers' Association.

The scandal showed that the BBA's processes were not up to the job and administration was handed to US derivatives exchange Intercontinental Exchange, which started running the rate on Monday.

During and before the financial crisis, traders and submitters of figures tried to manipulate the rate either to profit from their bets on interest rates or to disguise the cost of their bank's borrowing.

The scandal forced former Barclays boss Bob Diamond out of his job and has cost banks such as Royal Bank of Scotland and Switzerland's UBS billions of pounds in fines.